Anti-theft device for vehicles

ABSTRACT

A vehicle anti-theft device which when activated by the vehicle user causes the fuel tank to be isolated from the internal combustion engine of the vehicle and simultaneously therewith causes the fuel gauge to register empty, thereby restricting movement of the vehicle upon unauthorized usage and creating the impression that no fuel is available for the vehicle.

SUMMARY OF THE INVENTION

This invention relates to an anti-theft device for a vehicle and willhave specific application to the isolation of the fuel tank from thevehicle combustion engine to prevent unauthorized use of the vehicle.

The anti-theft device of this invention includes a valve placed withinthe fuel line between the fuel tank and the combustion engine of thevehicle. The valve is electrically actuated and is connected by a switchmember through the ignition switch to the power supply for the vehicle.The valve is normally located in its closed position, isolating the fueltank from the vehicle engine. The switch member is also associated withthe fuel gauge for the vehicle in such a manner so that when the switchmember is located in its anti-theft position, the valve between the fueltank and engine will remain in its closed position and the fuel gaugewill indicate "empty" when the ignition switch is turned to start thevehicle engine. With the switch member in its anti-theft position themotor will start and then only continue to run until the fuel in thatpart of its fuel line which is isolated from the fuel tank is consumed.

With the fuel gauge indicating "empty," the unauthorized vehicle user isprovided the impression that the vehicle is out of fuel. With the switchmember located in its operative position, the valve in the fuel linebetween the fuel tank and engine opens when the ignition switch isturned on to allow for the normal operation of the engine as well as thenormal indicating function of the fuel gauge.

Accordingly, it is an object of this invention to provide a device forpreventing the unauthorized taking of motor vehicles.

Another object of this invention is to provide an antitheft device ofsimplified and reliable operation for installation in vehicles, such asautomobiles and trucks.

Still another object of this invention is to provide an anti-theftdevice for motor vehicles having diesel or gasoline powered combustionengines.

Other objects of this invention will become apparent upon the reading ofthe invention's description.

BRIEF DESCRIPTION OF THE DRAWING

A preferred embodiment is chosen for the purposes of illustration anddescription wherein;

FIG. 1 is a diagrammatic view of the invention incorporated into thepower system of a vehicle.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment illustrated is not intended to be exhaustive orto limit the invention to precise form disclosed. It is chosen anddescribed in order to best explain the principles of the invention andits application and practical use to thereby enable others skilled inthe art to best utilize the invention.

The power system of the motor vehicle shown diagrammatically in FIG. 1includes a combustion engine 10, a fuel tank 12, a fuel line 14extending from tank 12 to engine 10, and a suitable fuel pump or ejectormechanism 16 located within the fuel line for the purpose of withdrawingthe fuel 18 from tank 12 and ejecting it into the cylinders of engine10. The particular type of fuel 18 utilized in engine 10 may be of anyof the variety of types utilized for combustion engines.

Mounted within the vehicle is a fuel gauge 20 which through a suitablemetering device 22 indicates the fuel availability within tank 12.Mounted also within the vehicle is an ignition switch 24 which, in turn,is connected to a suitable electrical power source 26, such as abattery, generator or combination battery and generator. Theaforedescribed power system for the motor vehicle is of standard formand construction with it being understood that a coil, starter and othersuitable items pertinent to the particular type of engine utilized inthe power system will be necessary to operationally complete the entiresystem but are not here illustrated for simplification purposes.

The anti-theft device of this invention includes a valve 28 placedwithin fuel line 14. Valve 28 is electrically actuated and has a normal"off" position when not energized to isolate fuel tank 12 from engine10. A switch member 30 is mounted within the vehicle in an accessiblebut preferably hidden location. Valve 28 is electrically connected topower source 26 through switch member 30 and ignition switch 24. Whenswitch member 30 is located in its operative position (connectingterminals 2 and 3, 1 and 4), valve 28 is electrically connected toignition switch 24 which when turned on serves to energize the valve,causing it to open to place fuel tank 12 in fluid communication withengine 10.

Switch member 30 is also connected to fuel gauge 20 in such a manner sothat when the switch is located in its antitheft position (connectingterminals 2 and 6, 1 and 5), the fuel gauge will be rendered inoperableupon activation of ignition switch 24 and its indicator 22 will register"empty" with valve 28 being de-energized so as to isolate fuel tank 12from engine 10. The particular manner in which fuel gauge 20 isdeactivated will vary depending upon the construction and manner ofoperation of the gauge. Typically, such gauges are coil actuated and areresponsive to variations in resistance or current created by variationsin the level of fuel within the fuel tank. In which case it will only benecessary to cause a grounding of the actuating current in the gaugewhen switch member 30 is shifted into its anti-theft position.

The manner of operation in the anti-theft device above described varieswith the positioning of switch member 30. When the switch member 30 isin its operative position, the actuation of ignition switch 24 causesvalve 28 to open permitting, during starting and continued normaloperation of the vehicle, fuel 18 to be drawn from tank 12 and deliveredto engine 10. Thus, with switch member 20 in its operative position, thepower system for the vehicle will operate in its normal intended manner.When it is desired to secure the vehicle against theft or unauthorizedusage, the user of the vehicle will shift switch member 30 into itsantitheft position to deactivate fuel gauge 20 and cause valve 28 whichis in its unenergized, closed position to be isolated from ignitionswitch 24 and power source 26. When ignition switch 24 is turned by anintruder to start the vehicle, the fuel gauge will register empty. Asengine 10 is started, only that portion of the fuel between valve 28 andthe engine will be fed to the engine thereby limiting the engine runningtime and thus preventing the vehicle from being driven an appreciabledistance. Should the intruder attempt to bypass the ignition switch inorder to start the vehicle, the anti-theft device of this inventionwould similarly operate as long as the intruder was not able to locateand actuate switch member 30.

Switch member 30 can also be electrically connected to a speed-up deviceor accelerator member 34 which is associated with the throttle of engine10. Accelerator mechanism 34 is activated when switch member 30 is inits anti-theft position and ignition switch 24 is turned to start engine10 and serves to cause the engine to run at a fast idle for the purposeof quickly consuming the fuel in fuel line 14 between closed valve 28and the engine. The use of accelerator mechanism 34 can either preventor substantially reduce the distance the intruder would be able to drivethe vehicle before the limited fuel supply to the engine is exhausted.This can be accomplished by bypassing the cruise control governor withan electrically actuated valve which when actuated with switch member 30in its anti-theft position and engine 10 started will cause a vacuum tobe drawn upon the cruise control diaphragm which opens the acceleratorof the vehicle.

It is to be understood that the invention is not to be limited to thedetails given but may be modified within the scope of the appendedclaims.

What I claim is:
 1. An anti-theft device in combination with a motorvehicle having a combustion engine, a tank containing fuel for saidengine, a fuel line connecting said engine to said tank, means fordrawing fuel from said tank and delivering the fuel to said engine tocause the operation of the engine, a fuel gauge associated with saidtank for indicating the amount of fuel therein, an electrical powersource, said power source connected by an ignition switch to said fuelgauge, said fuel gauge having an indicator means shiftable between fulland empty positions for indicating the amount of fuel in said tank whensaid gauge is energized by said power source, said ignition switchhaving an on position causing said fuel gauge to be energized and an offposition, said anti-theft device comprising a valve connected to saidfuel line between said engine and fuel tank, said valve having a normalclosed position isolating said tank from said engine, a switch membercarried by said vehicle in a hidden location having first and secondoperative positions, said valve being operatively connected to saidpower source through said ignition switch and switch member, said valvebeing shifted into an open position when said ignition switch is shiftedinto its on position and said member is in its first position, saidvalve being in its closed position when either said ignition switch isshifted into its off position or said switch member is in its secondposition, and means associating said switch member with said fuel gaugefor causing said indicator means of the fuel gauge to be located in itsempty position when said switch member is in its second position wherebysaid fuel tank will be isolated from said engine and said fuel gaugewill indicate empty regardless of the position of said ignition switch.2. The anti-theft device of claim 1 and means associated with saidengine for accelerating the operation thereof when said switch member isin its second position to utilize the fuel in said fuel line betweensaid valve and engine.